Process for the alkylation of hydrocarbons



Feb. 18, 1947. M. P. MATuszAK PROCESS FOR THE ALKYLATION OF HYDROC'ARBONS Filed May l2, 1945 Patented Feb. i8, i947` PROCESS FOR THE LKYLATEON OF HYDROCONS Maryan P. Matuszak, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware l This invention relates to an improved process for the conversion of hydrocarbons. In a particular aspect this invention relates to the allWlation of low-boiling isoparaiiln hydrocarbons in the presence of a hydrogen fluoride-containing catalyst by reaction with low-boiling olens. In this particular aspect this invention relates to a novl process for the alkylation of isobutane with an olefinic mixture comprising butene-l and butene2 in the presence of hydroiiuoric acid to produce an alkylate of high quality.

A This invention is a continuation-impart of my copending application, Serial No. 550,447, led August 21, 1944, which in turn is a, continuationin-part, insofar as any common subject matter is concerned, of my copending applications, Serial Nos. 467,872 (now Patent No. 2,399,368, issued April 30, 1946), 467,873, and' 467,874 (now Patent No. 2,387,162, issued October 16, 1945), all of which were filed on December 4, 1942; the lastmentioned application is a continuation-impart 'of application Serial No. 395,282, iiled May 26,

1941, now Patent No. 2,320,629, issued June 1, 1943. This invention is an improvement of the alkylation process described in the copending application of Frederick E. Frey, Serial No. 545,309, iiled July 17, 1944, which is a continuation-inpart of Serial No. 450,588, tiled July 11, 1942, now Patent No. 2,384,294, issued September 4, 1945, in which process the hydrofluoric acid catalyst is modied or tempered by the presence of a soluble compound containing a nitrogen atom basic to hydrofiuoric acid.

` In a typical method of conducting an alkylation reaction, an alkylatable hydrocarbon is agitated with hydrouoric acid to produce a liquid mixture or emulsion which is maintained at a reaction temperature suitable for alkylation, and an alkylating reactant, such as normal butene, is introduced in such a way as to maintain a very low `concentration of alkylating reactant in the mixture. After a suitable reaction time the hydrocarbon layer may be decanted, and the juncture product or alkylate may be separated from other hydrocarbons, as by fractional distillation.`

Application May 12, 1945, Serial No. 593,462

18 Claims. (Cl. Zim-683.4)

of parafn to olefin of about 2:1 to about is suitable as the composition of the feed in ef-4 fecting the reaction; however, the ratio of paraii'in to olen in the reaction zone itself is much greater, preferably 100:1 or more. About 0.5:1 to about 4:1 volume ratio of hydrogen fluoride to hydrocarbon is the preferable concentration for catalyzing the alkylation reaction. The appropriate reaction time in -the reaction zone may vary'frcm about one to about thirty minutes.

The alkylating reactant which is contacted with the alkylatable hydrocarbon in the reaction zone is obtained vfrom conventional refinery sources and usually comprises a mixture of 1-oiefins and 2olens. Since it is known that l-olefins react with the alkylatable hydrocarbon, such as-isobutane, to form an alkylate having an octane number relatively lower that than ,for an alkylate produced by reacting with 2-olens, it

has been found particularly desirable in some cases to limit the alkylating reactant composition to 2-olens, such as butene-Z, etc. For example, the alkylation of isobutane with butene-l in the presence of hydrogen fluoride produces an ali kylate which has an octane number of about 89;

while alkylation oi isobutane with butene2 produces an alkylate which has an octane number of about 92. I 'I As indicated in my aforementioned copending application, Serial No. 467,873, an alkylating reactant which may comprise a 1olen or a mixture of a l-olen and a 2-o1en is isomerized to convert the 1oleiin to the 2-olen, and subsequently the isomerized alkylating reactant is used to alkylate anv alkylatable hydrocarbon to form a product which has a higher octane number than would normally be realized without isomerizing the 1-olefin to the 2-olen.

As an alternative method of obtaining an a1- kylate of high octane quality without the aforementioned isomerization of -l-olefiris in the alkylating reactant, the present invention provides a unitary, integrated process for alkylating isoparailins with both 1-oiens and 2-olens in the presence of a hydrofluoric acid alkylationcatalyst, each type of olefin being used to alkylate the isoparaiiin under conditions peculiarly adapted to obtaining an yalkylate of optimum yield and octane quality. The process of Athe present invention is especially adaptable to alkylation of minimum of equipment and'with less expenditure of time, effort and materials than is required by a process characterized by separate isomerization of 1-olens to 2-oleiins, followed by a hydrouoric acid alkylation of the alkylatable hydrocarbon with an isomerized olefin.

Among the objects of this invention is to provide an improved process for the conversion of hydrocarbons.

Another object is to alkylate low-boiling isoparamns to suitable motor-fuel hydrocarbons.

An object of this invention is to shorten the reaction time in the alkylation of low-boiling isoparains with olens in the presence of hydrogen uoride.

Still another object is to provide an improved process for alkylating isobutane with normal butene, whereby the alkylate obtained has an ctane rating higher than that of the alkylate obtained under comparable conditions by convenv tional hydrouoric acid alkylation.

A further object is to increase the yield of light alkylate in the alkylation of low-boiling isoparaiiins in the presence of hydrogen uoride.

Still a further obiect is to provide a process for the alkylation of low-boiling isoparains with an olenic mixture comprising butene-l and bu- Y tene-2 in the presence of hydrogen fluoride as the alkylation catalyst.

Other objects and advantages will become apparent from the accompanying description and disclosure.

Much to my surprise, I have found that, in an alkylation process catalyzed in particular by a hydrouoric acid-containing catalyst, certain compounds may be advantageously added to the l acid, to the reaction mixture orto the reactants in an appropriate amount, hereinafter described, to promote the formation oi' an alkylate of superior' quality. Further, I have found that these compounds can be recovered and recycled tothe process.

Compounds which may be used to promote the monium uoride, ammonium biuoride and the likerfmay be-used also with satisfactory results.

y It hasbeen found that such basic nitrogen compounds are notl particularly benecial, although not detrimental, when an` isoparafdn is alkylated with an isoolen, such. asv isobutene, in the presence of hydrogen fluoride. For this reason, the

basic nitrogenY compounds are used as promoters according to. this invention preferably only when a substantial amount of a normal oleiin comprises the alkylating reactant.

In accordanceyrith one aspect of this invention.' I- have found that the formation of alkylae hydrocarbons of especially high octane number is promotedby the presence of a minor or limited proportion of a basic nitrogen compound, such as ammonia, quinoline, etc., in the hydrofiuoric acid. In the case of using ammonia. .the ammonia may be introduced as such or as an ammonium salt. preferably an ammonium iiuoride and most preferably ammonium biiiuoride. The proportion of ammonia or other basic nitrogen compound should be between approximately 1 and approximately mole per cent of the total vhydrogen iiuoride, considered as the monomer, exclusive oi.' any dissolved matter, when normal butene is the alkylating olen. The optimum proportion for any particular set of selected alkylation conditions maybe readily determined by trial; usually the optimum proportion' in alkylating isobutane with butene-l. is between about 4.5 and about 6.5 mole per cen't, so that the proportion is preferably adjusted to approximately 5.5 mole per cent. This proportion is rather critical from the point of view of obtaining an alkylate of the highest possible octane rating. If too little ammonia is present, the alkylation degenerates into the conventional hydroiluoric acid-catalyzedalkylation; if too. much is present, the oleiin is consumed in formation of the corresponding alkyl uoride, accompanied by considerable polymerization, and the Aresulting product is inferior in both yield and octane. rating and contains an excessive proportion of organic uorine compounds. Furthermore; the critical limits of the proportion of ammonia in hydrouoric acid alkylation with butano-2 appear to differ somewhat from those for butene-l, under otherwise substantially identical alkylation conditions. That is, in alkylation of isobutane with butene-Z, the optimum proportion of ammonia appears to be between about 2.5 and about 4.5 mole per cent .ofthe hydrogen iiuoride in the catalyst; so that the proportion is preferably maintained at approximately 3.5 mole per cent. For alkylating an isoparain with a mixture of normal butenes, the preferred proportion of ammonia should be adjusted in accordance with the proportions of the butene-l andbutene-Z in the mixture; for. examp1e, for a'.- mixture containing approximately equal proportions of butene-l and of butene-Z, the preferred proportion 50 of ammonia is approximately 4.5 mole per cent of .the hydrogen uoride in the catalyst. In a1- kylatingwith solely isobutene, however, no ammonia preferably should be .present in the catalyst; hence, when the alkylation is being made 55 with a mixture containing isobutene and one or both normal butenes, the proportion of am# monia'should be adjusted in accordance with the proportions of the specic butenes present. For example, for alkylating with a mixture containing approximately equal proportions of butene-l,

butene-Z, and isobutene, the proportion of ammonia should preferably be adjusted to approxi-: mately 3.2 mole per cent of the hydrogen uoride.

It will be understood that adjusting the propo'rg 05 tion of ammonia in this manneris in the interest of obtaining the optimum octane rating f Qr the over-all alkylate produced andthat other` basic nitrogen compounds may be used in place-orammonia in equivalent amount. Y However, ammonia is preferred as being most economical. *A

This invention-is equally app1i9able tothe hydroiiuoric acid alkylation of- 'other isoparailins, such as isopentane. etc., with normal o1ens-in general, Thus, such -limitations of concentrafv tions or the basicnitrogen compound which de.'-

pend upon the structure of the normal olefin such of the nitrogen atom in ammonia or similar compounds to form an ammonium ion by union with a proton or other actual or virtual positive ion. Because of this tendency of the nitrogen compound, the formation of actual or virtual ions from isoparains in 'the presence of hydrogen uoride appears to be promoted by shifting to the right of such equilibria as the following:

--i-i-i- 2- -i -i-aisobutane methium isopropide -i-i-I- e -i -a-i isopentaue methium isobutide In this mechanism, the basic nitrogen compound, such as ammonia, quinoline, etc., promotes the ionization of the parafiins by acting as a hydrium spectively. Dashes perpendicular to an atom represent bonds or shared pairsof ele'ctrons between two carbons atoms or between a carbon atom and a hydrogen atom; dashes parallel to an atom represent unshared or lone pairs of electrons.)

For further details of this explanation, which is theoretical in nature. the aforementioned copending application may be consulted.

A detailed description of one embodiment of this invention may be made with reference to the accompanying drawing, which is a schematic flow-diagram exemplifying a preferred manner of tion columns. From this system, butene-l is passed through conduit II to the isobutane stream in conduit 3; undehydrogenated normal butane is recycled through conduit I2 to dehydrogenator 8; butene-2 is passed through conduit I3 to the isobutane stream in conduit 4; and byproducts of the dehydrogenation are removed, mostly as a low-boiling fraction, in a manner l not shown) obvious to those skilled inthe art.

In each of alkylators 5 and 6,the incoming mixture of isobutane and normal butene is intimately mixed under alkylation conditions with an alkylation catalyst, which enters the alkylator from conduit I4 or I5, respectively. For alkylator 5, in which the alkylating butene is butene-l, the catalyst is concentrated or substantially anhydrous hydrofluoric acid containing approximately 5.5 mole per cent of ammonia; for alkylator 6. in which the alkylating butene is butenZ, the catalyst is concentrated or substantially anhydrous hydroluoric acid containing approximately 3.5 molek per cent .of ammonia. Execpt for the difference in ammonia content of the hydrofluoric acid, the alkylation conditions in the two alkylators may be substantially alike. Preferably, the pressure should be sufficient to maintain the reaction mixture in liquid phase, but above this point it may be as high as may be desired for such purposes as effecting proper movement of the various streams in the system or the like. The temperature and the contact time, or average time of residence or mixing in the alkylator, may vary widely; for a temperature in the range of about 90 to about 120 F., which is preferred as being readily obtainable by water-cooling, the contact time may be from about 3 to about 20 minutes, preferably approximately 10 minutes. The volume ratio. of hydrocarbons to hydroiiuoric acid in the alkylator may be from about 1:1 to about .4:1, preferably approximately 1:1. 'Ihe mole ratio of isobutane 'to butene in the incoming hydrocarbon stream is preferably as vhigh as is economically feasible, usually it is from 4:1 to 10:1, and a much higher ratio inthe reaction zone itself.

The reaction mixture eilluent from alkylator 5 is passed through conduit I6 t0 separator I1, in

- which it is separated by gravity into two liquid through conduit converting four-carbon parafllns to motor-fuel it is catalytically dehydrogenated to normal bui tenes. The resulting dehydrogenation eiliuent is passed through conduit 9 to fractionator I0, which comprises a system of fractional-distillaphases, one a hydrocarbon phase and the other a heavier hydrogen fluoride phase. The hydrocarbon phase may be passed through conduits I8, 20 and 34 to fractionator I9 for separation into various fractions, but it is preferably passed directly I8 to extractor 2I for removal of organic fluorine compounds by extraction with substantially ammonia-free anhydrous hydrofiuoric acid, which is introduced through conduit 22, in a manner similar to that indicated in the aforementioned Patent No. 2,320,629. The hydrouoric acid phase from separator Il in part is recycled through conduit `I4 to alkylator 5 and in part is passed through conduit 24 to fractionator 25. From fractionator 25, substantially ammonia-free' hydrouoric acid, accompanied by some light hydrocarbons, is passed overhead through conduit 22 to extractor 2l; and a kettle product from fractionator 25, substantially free from free hydrofluoric acid, is passed through conduit 50 to separator 5I, in which it is separated into ammonium uoride and `a tar or oil. The tar or oil is withdrawn from the process, as through outlet 29, and may be treated to recover any ,entrained ammonium fluoride and/or any other iiuorine compounds (not shown). The ammonium fluoride. preferably after addition of sumcient `anhydrous hydroiluoric acid toit to dissolve it (not shown) is ordinarily passed in part directly through conduits 25:.V and I4 to alhlator and in part through conduits 2l, 21, and I5 to alkylator 5, but part or all of it may be withdrawn, if desired, through outlet 23. Make-up anhydrous hydroiluoric acid may be added to the system as required through inlet 3l, and makeup ammonia is added as required through inlet 3l, preferably as ammonium iluoride or biiluoride and most preferably as a. solutiton in substantially anhydrous hydroiluoric acid.

The reaction mixture eiiluent from alkylator 6 is passed through conduit 32 to separator 33, in which. it is separated by gravity into two liquid phases, one a hydrocarbon phase and the other a heavier hydrogen fluoride phase. The hydrocarbon phase may be passed through conduits 35 and 34 to fractionator I9, for separation into 'rarious fractions, but it is preferably passed directly through conduit 35 to extractor 2| for removal of organic fluorine compounds by extraction with hydrouoric acid; inasmuch as: this hydrocarbon phase at times contains slightly less organic liucrine than the hydrocarbon phase from separator 25, it is preferably introduced into extractor 2l at a point correspondingly relatively upstream with respect to the stream of extracting acid. The hydrouoric acid phase from separator 33 in part is recycled through conduit I5 toalkylator 6 and in part may bewithdrawn through conduit 31 and outlet 38 or, preferably, is passed through conduit 31 directly to fractionator 25 for purification. Make-up anhydrous hydroiluoric acid may be added to the system through inlet 39, but it is preferably added entirely through inlet 40 and line 22 to extractor 2|; make-up ammonia, when required, may be added to the system through inbut ordinarily sufdcient ammonia is brought as ammonium fluoride and/or bifluoride through conduit 2l.

From extractor 2| the hydrotluoric acid extract is passed through conduits 42 and l5 to alkylator 5, carrying with it the extracted organic iiuorine compounds, which thus become available for the alkylation in alkylator 6 with advantageous recovery of the organic fluorine as hydrogen fluoride.

From extractor 2l theorganic iluorine-depleted hydrocarbon mixture is passed through conduits 43, and 34 to fractionator I9, which generally is a system of fractional-distillation columns. .From this system hydroiiuoric acid dissolved in the hydrocarbon mixture is distilled overhead together with some isobutane and is passed through conduits 44, 42 and I5 to alkylator 5. Isobutane is recycled to alkylators 5 andi through conduits 45 and 46, as shown. Normal butane is withdrawn through outlet 47, or is passed to dehydrogenator 8 by means not shown. A motor fuel of high octane rating is withdrawn as the principal product of the process through outlet 48. A small fraction of heavy hydrocarbons may be withdrawn through outlet 49.

It will be understood that the now-diagram is schematic and that auxiliary equipment, not shown or described, such as pumps, valves, controllers, and the like, may be desirable or even necessary at various points in the process. As such auxiliary equipment are well known, they andere Two continuous pilot-plant runs were made for the alkylation of isobutane with butene-l under similar alkylation conditions except that in one run the anhydrous hydrofluoric acid contained about 5 mole per cent of ammonia, introduced as ammonium biiiuoride whereas m the other run the acid was ammonia-free. The data obtained may be summarized as follows: i

Run With 5.3% Without NH; NH:

Temperature, F. 91 88 Pressure, p. s. i l 130 Contact time.r min. l0. 4 ll. l Isobutauelbutene (mol) 4. 7 4. 1 Hydrocarbons/HF (vol.) 1.13 1.15 Total debutanized alkylate:

Yield, wt. per cent of butene 203 192 Gravity, A. P. L 67.9 67.8 Reid vapor pressure, lb 2. 75 A. S. T. M. distillation, F.

First drop 127 162 10% evap 193 203 507 evap.. 226 227 90% evap 317 29a End omt 412 463 S. T. octane number 89.2 85.3 Composition, vol. per cent Pentanes 4.5 3.9 Hexanes 6. 7 3. Heptanes 6.9 3. Octanes 65. 9 73. Nonanes 2. 3 l. Decanos 4. l 2. Heavier 9. 6 ll. Light alkylate:

Cut point, F 365 365 Yield, vol. per cent of total alkylate... 93. 7 92. 5 Gravity, A. l. I 68.6 69.0 Reid vapor pressure, lb 2. 80 A. S. T. M. distillation, F First drop 158 151 10% evap 197 204 50% evap 223 224 90% evap 254 250 End point 305 368 A. S. T. M. octane number 89.4 87. 4

It will be noted that the octane number of the total alkylate was increased by 3.9 units because of the presence of the ammonia in the hydrouoric acid, and that the octane number of the light or aviation-range alkylate was increased by 2.0 units. Furthermore, it will be noted that the light alkylate constituted 93.7 per cent by volume of the total alkylate when ammonia. was present, whereas it was only 92.5 per cent when ammonia was absent; inasmuch as the yield of total alkylate was 203 and 192 mole per cent of the original butene-l, respectively, this fact indicates that an advantageously higher yield of light alkylate is vobtained from the oleiin when ammonia is preslow value for this ratio, even though it causes the can be readily supplied by those skilled in the The following data are illustrative of some of the many aspects of the invention, without being necessarily limitative.

yield and the quality of the alkylate to be somewhat adversely aiec'ted. When as at present, the need for high-quality alkylate is great, the available alkylation equipment is quite limited,

land the amount of isobutane is insuihcient for all needs, it is desirable to conduct the alkylation at a fairly low mole ratio of isobutane to olen. in the interest of obtaining as much alkylate as possible from the aavilable isobutane with the available equipment. Also, for a given output of alkylate, the concomitant-undesirable isomerization of isobutane to normal butane vthat occurs with these considerations, it maybe observed that the yield and th'quality of the alkylate obtained in' the run made without yammonia reflect the inuence of the ratio of isobutane to butene-l, for at a mole ratio twice as rlarge the yield of light alkylate is approximately 98 per cent' by volume of the total alkylate andthe octane number is approximately 89. Butin the run made with ammonia, the yield and the octane number of the alkylate approach the relatively higher values that are obtained in hydroiiuoric acid a1- kylation of isobutane with butene-2 without ammonia at a mole ratio of isobutane to olefin approximately twice that used in the present run. In other words, this run illustrates the unexpected but important advantage of overcoming to a considerable degree the unfavorable influence attending a low value for the ratio of isobutane to olen in the feed.

Inasmuch as this invention may be practiced otherwise than as specically described or illustrated, and inasmuch as many variations and modifications o f it will be obvious to those skilled in the art, this invention should not be restricted otherwise than by the disclosure and accompanying drawing.

Having described my invention, I claim:

l. 'Ihe process for the alkylation of isobutane with butenes in the presence of a hydrofiuoric acid alkylation catalyst which comprises passing a butene fraction to a fractional distillation, separating said butene fraction into a fraction comprising butene-1 as an essential olefin constituent and a fraction comprising butene-2 as an essential olen constituent, introducing said butene-l fraction together with isobutane and a hydroiiuoric acid alkylation catalyst containing about 4.5 to about 6.5 mole per cent of ammonia into an alkylation zone, maintaining the contents of said alkylation zone under alkylation conditions, separating eflluents of said alkylation Zone into a liquid hydrocarbon phase and a liquid hydroiiuoric acid phase, passing said hydrocarbon phase to a fractional distillation and recovering a hydrocarbon fraction comprising higher-boiling hydrocarbons produced by said alkylation as a product of the process, passing at least a portion of said hydrofluoric acid phase to a fractional distillation to recover as a low-boiling fraction purified hydroiluoric acid'and as a high-boiling fraction a mixture comprising ammonium fluoride together with tar and oil as impurities, separating said ammonium fluoride from said tar and oil, and passing a portion of said ammonium iiuoride back to said butene-1 alkylation zone, separately introducing said butene-2 fraction together with isobutane and a hydrouoric acid alkylation catalyst containing about 2.5 to about 4.5 mole per cent of ammonia into an 2. A process for alkylating isobutane with a mixture of normal butenes comprising substantially equal proportions of butene-1 and butene-2 in the presence of concentrated hydrofiuoric acid as a catalyst, which comprises reacting said isobutane with said normal butenes under alkylation conditions and in the presence of a hydroiluoric acid alkylation catalyst containing approximately 4.5 mole per cent of ammonia, and recovering from an eiiiuent of said alkylation paraffin hydrocarbons of high octane number as a product of the process.

3. A process for alkylating isobutane witha mixture of butenes comprising substantially equal proportions of isobutene, butene-1, and butene-2 in the presence of concentrated hydrouoric acid as a catalyst, which comprises reacting said isobutane with1 said butenes under alkylation conditions and in the presence of a hydrouoricl acid catalyst containing approximately 3.2 mole per cent of ammonia, and recovering from an eiiiuent of said alkylation paraihn hydrocarbons of high octane number as a product of the process.

4. A process for alkylating isobutane with a mixtureof normal butenes in the presence of concentrated hydroluoric acid as a catalyst, which comprises reacting said -isobutane with said normal butenes under lalkylation conditions and in the presence of a hydrofluoric acid alkylation catalyst containing approximately 4.5 mole per cent of ammonia, and recoveringfrom'an eiilualkylation zone, maintaining the contents of f said alkylation zone under alkylation conditions, separating effluents of' said alkylation zone into a liquid-hydrocarbon phase and a liquid hydrofiuoric acid phase, passing said hydrocarbon phase to the aforesaid hydrocarbon phase fractional distillation, passing at least a portion of said hydrofluoric acid phase to the aforesaid .fractional distillation for the separation of ammonium iiuoride from hydroiiuoric acid, and passing a portion of said ammonium fluoride after the aforesaid separation of tar and oil therefrom to said butene-2 alkylation zone.

ent of said alkylation paraiiin hydrocarbons of high octane number as a product of the process.

5. In a process for reacting visoloutane with normal butenes in the presence of concentrated hydroiluoric acid as the alkylation catalyst t0 produce parain hydrocarbons having high octane numbers, the improvement which comprises separating a-mixture of normal butenes into a fraction comprising butene-1 as the essential oleiin constituent and a fraction comprising butene-Zas the essential oleiin constituent, reacting said butene-lfraction with isobutane under alkylation conditions and in the presence of a hydroiluoric acid alkylation catalyst containing about 4.5 to about 6.5 mole per cent of a basic nitrogen compound, separately reacting said butene-2 fraction with isobutane under alkylation conditions and in the presence of a hydrouoric acid alkylation catalyst containing about 2.5 to about 4.5 mole per cent of a basic nitrogen compound, combining at least a portion of the eflluents of each said alkylation and vrecovering from the combined eiuents paraffin hydrocarbons of high octane number as a product of the process. y

6. The process ofclaim 5 in which said basic nitrogen compound is ammonia.

7. The process of claim 5 in which said basic nitrogen compound is quinoline. l

8. The process of claim 5 in which said basic nitrogen compound is an acid amide.

9. The process of claim 5 in which said nitrogen compound is acetamidel i 10. The process of claim 5 in which said nitrogen compound is ammonia and is added as `ammonium bifiuoride.

vhigh octane numbers, the improvement which comprises separating a mixture of normal butenes into a fraction comprising butene-1 as the essential oleiin constituent and a fraction comprising butene-2 as the essential olein'constituent, reacting said butene-l fraction with a lowboiling isoparain under alkylation conditions and in the presence of a hydrouoric acid alkylation catalyst containing about 4.5 to about 5.5

4.5 mole per cent of a basic nitrogen compound,"

combining at least a portion-of the emuents of each said aikylation and recovering from the combined eiiluents paranvhydrocarbons of high octane number as a product of the process..

12. An improved process for reacting a lowboiling isoparamn with low-boiling normal oiens in the presence of concentrated hydrofluoric acid as the alkylation catalyst to produce parain hydrocarbons having high octane numbers, which comprises separating a mixture of low-boiling oleilns into a fraction comprising 1-oleins as the essential olefin constituent and a fraction comprising 2-oleins as the essential olefin constituent, reacting saidl-oleiln fraction with a lowboiling isoparain under `allrylation conditions and in the presence of a hydroiiuoric acid aklylation catalyst containing about 4.5 to about 6.5

mole .per cent of a basic nitrogen compound. separately reacting said 2-4olen fraction with a lowboiling isoparafiin under alkylation conditions and 1n the presence of a hydrofluoricl acid alkylation catalyst containing about-2.5 to about 4.5 mole per cent of a basic nitrogen compound. com bining at least a portion of the veffluents of each said alkylation and recovering from the combined eiliuents paraiiin hydrocarbons of high octane number as a product of the process.

'13. `An improved process forreacting a lowboiiing isoparain with low-boiling normal olens in the presence of a hydrouoric acid-containing catalyst as the alkylation catalyst to produce parafiin hydrocarbons having high octane numbers, which comprises separating a mixture of low-boiling olens into a fraction comprising l-olefin as the essential olen constituent and a fraction comprising 2olefins as the essential olen constituent, reacting said l-olefln fraction lation and recovering from th'e combined eiuents parailin hydrocarbons of highoctane number as a product of the process.

14. In a process for the alkylation oi' isobutane with butenes comprising normal butenes in the presence of a hydroiiuoric acid-containing cata-V lyst, the improvement which comprises maintaining insaid hydrouoric acid-containing catalyst a content ofl a basic nitrogen compound in mole per cent of hydrogen uoride present within a range, the approximate lower limit ot which is determined by '4.5 times the mole traction of bntene-l of the total of said butenes plus 2.5 times the mole fraction oi! -butene-il of the total of said butenes and the approximate upper limit of which is determined by 6.5 times mole fraction of butene-l of the total of said butenes plus 4.5 'times the mole fraction of butano-2 of the total of said butenes.

15. In a process for the alhlatlon of isobuf tane with .butene-l in the presence o! a hydroiluoric acid-containing, catalyst, the improvement which comprises maintaining in said hydrouoric acid-containing catalyst a content o! a basic nitrogen compound within the range ot about 4.5 to about 6.5 mole per cent of the hydrogen fluoride present.

16. In a .process for the alkylation of iso'butane with butene-Z in the presence oi! a hydroiiuoric acid-containing catalyst, the improvement which comprises maintaining in said hydrofiuoric acidcontaining catalyst a content of a basic nitrogen compound within the range of about 2.5 to about 4.5 mole per cent of hydrogen fluoride present. v1'1. In a process for the alkylation of a lowboiling isoparafiin with low-boiling olens comprising normal olens in the presence of a hydrouoric acid-containing'catalyst as the alkylation catalyst. the improvement which comprises maintaining in said hydrouoric acid-containing catalyst a content of a basic nitrogen compound in mole per cent of hydrogen fluoride present within a range, the approximate lower limit of which range is determined by 4.5 times the mole fraction of l-olen of thetotal of said olens plus 2.5 times the mole fraction of 2-oleiln of the total of said olens and the approximate Vupper limit of MARYAN P. MATUSZAK.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS' Number Name Date 2,276,251 Morrell Mar. 1o, 1942 2,317,694 ott Apr. 27, 1943V 2,322,800 Frey June 29, l194:.

2,320,629 Matuszak June 1, 1943 

